hGH enhances dTMP-induced platelet production. (A) Viability of M07e cells cultured with dTMP (20 ng/ml, 50 ng/ml, or 100 ng/ml) for 72 hours was analyzed by CCK-8 assay. The data are from 6 independent assays with a single batch of cells. Error bars denote SD. **P < .01. (B) Human cord blood-derived CD34⁺ cells were cultured with dTMP (20 ng/ml, 50 ng/ml, or 100 ng/ml) for 10 days and then the proplatelet formations were observed under a phase-contrast microscope. Histogram shows the number of proplatelet-forming megakaryocytes. Data are from 3 independent experiments. Error bars denote SD. **P < .01. (C) Human cord blood-derived CD34⁺ cells were cultured with dTMP (20 ng/ml, 50 ng/ml, or 100 ng/ml) or rhTPO (20 ng/ml) for 13 days. (i) Culture-derived platelets stained with APC-CD41, FITC-CD42b, and PI was analyzed by flow cytometry. (ii) Histogram showing the percentage of CD41⁺CD42b⁺PI⁻ culture-derived platelets from 3 independent experiments. Error bars denote SD. *P < .05; **P < .01. (D) Human cord blood-derived CD34⁺ cells were cultured with dTMP (20 ng/ml) in the absence or presence of rhGH (100 ng/ml) for 10 days. Proplatelet formations in representative megakaryocytes were stained with β1-tubulin (green) and DAPI (blue), and visualized by confocal microscope. (E) The expression level of β1-tubulin in human cord blood-derived CD34⁺ cells cultured with dTMP (20 ng/ml) in the absence or presence of rhGH (100 ng/ml) for 10 days was analyzed by western blot (i) and the cells were visualized by TEM (ii). DM, demarcation membrane; N, nucleus. (F) Histogram showing the number of proplatelet-forming megakaryocytes for each group. Data are from 3 independent experiments. Error bars denote SD. **P < .01. (G) Human cord blood-derived CD34⁺ cells were cultured with dTMP (20 ng/ml) in the absence or presence of rhGH (100 ng/ml) for 13 days. Histogram shows the percentage of CD41⁺CD42b⁺PI⁻ culture-derived platelets in 3 independent experiments. Error bars denote SD. **P < .01.